There have been known vacuum apparatuses for reducing the internal pressure of a vacuum chamber by using a roughing pump and a main pump (e.g. Patent Literature 1).
FIG. 23 shows the configuration of a vacuum apparatus pertaining to Patent Literature 1. The vacuum apparatus includes mainly a vacuum chamber 91, a roughing pump 92 and a main pump 93.
The vacuum chamber 91 is a container within which processes of thin film formation, etching, drying of a coating film according to a coating film formation method (e.g. Patent Literature 2), and so on are performed.
The roughing pump 92 is used for rough pumping, or evacuation as the next stage to evacuation by the main pump 93. Rough pumping is pumping for reducing the internal pressure of the vacuum chamber 91 to the vacuum range in which the main pump 93 can operate. As the roughing pump 92, a mechanical vacuum pump such as a mechanical booster pump can be used, for example. In rough pumping, the air within the vacuum chamber 91 is exhausted by operating the roughing pump 92 with a roughing valve 94 open.
The main pump 93 is used for main pumping after the internal pressure of the vacuum chamber 91 has been reduced by the roughing pump 92. The main pump 93 is interposed between the vacuum chamber 91 and the roughing pump 92. As the main pump 93, a non-mechanical vacuum pump such as a cryogenic pump is used, for example. During the main pumping after the rough pumping, the air within the vacuum chamber 91 is evacuated by operating the main pump 93 and the roughing pump 92 with the roughing valve 94 closed and main valves 95 and 96 open.
Such a vacuum apparatus allows for reduction of the internal pressure of the vacuum chamber 91 to high vacuum or ultra-high vacuum.